Rotary underreamer



Jan. 10, 1933. 0 1,893,693

ROTARY UNDERREAMER I Filed Jan. 24. 1931 2 Sheets-Sheet l InventorPatented Jan. 10, 1933 UNITED STATES PATENT OFFICE mo FRANK A101, 63FEUWATHGTON PARK, CALIFORNIA, ASSIGNOB T0 JOHN GRANT, 0F 10S ANGELES,CALIFORNIA EGTBLRZ UNDERBEAME'R Application filed January 24, 1931.Serial No. 510,988.

This invention has relation to underreamers, particularly underreamersof the rotary type for use in deep wells; and a general object of theinvention is to provide a hydraulically actuated reamer of simple andefiective form.-

A further object is to provide a reamer which, when actuated to expandedposition by hydraulic pressure, is locked and. held in that expandedposition by arrangements inde endent of hydraulic actuation; so thatfailure or cessation of the hydraulic pressure does not in itself causecontraction of the reamer. And a further object is to provide, in such areamer as is here contemplated, a suitable arrangement whereby thecutters ma be effectively contracted.

hese and other objects of the invention are embodied in the underreamerherewith illustrated and hereinafter described as typical andillustrative of the invention: in such a. typical embodiment 1 haveutilized the swinging type of cutter-cutters which swing outwardly uponvertical axes on the reamer body. Such cutters, when swung outwardly toa certain amount of expansion will engage the walls of the hole in sucha manner that reaming action of the reamer will carry the cutters totheir fully expanded positions and will thereafter hold them in expandedposition independently of any other expansive force. Such cutters may becontracted either by rotating the tool reversely or by pulling them upinto contact with the casing or casing shoe, the heads of the cuttersbeing provided with suitable surfaces to cause contracting swinging uponengagement with the casing.

Preferably utilizing cutters of such a type,

my invention provides a simple form of hy-- draulic expansion mechanismin a form typified by push rods which extend diagonally downwardly andoutwardly to bear upon the cutters and which have, at their inner ends,suitable arrangement for taking hydraulic pressure in the centralcirculating passage of the tool. In the present instance I have shown amember in the form of a ball resting upon the upper inner ends of thepush rods and, when the push rods are in and up,

sion of the cutters.

In the drawings,

Figure 1 is a central longitudinal section showlng my reamer incontracted osition; Fig. 2 is a similar view showing t e parts inexpanded position;

Fig. 3 is a section on line 33 of Fig. 1; Fig. 4 is a section on line4-4 of Fig. 2; Fig. 5 is a section on line 55 of Fig. 2; Fig. 6 is asection on line 6-6 of Fig. 2. A suitable body for the reamer is shownat 10, the body being provided with the longitudinal circulation passage11 common to such tools. Near the upper end this circulation passage isenlarged as at 12 to form an enlarged chamber; and at the upper end ofthis chamber is located a bushing 13 having an orifice 14 and a ballseat 15. Orifice 14 forms part of the circulation passage and the seat15 forms a seat for ball 16. Bushing 13 ma conveniently be locateddirectly under t e screwthreaded ta r pin 17 which forms one member ofthe oint attaching the reamer body to drill stem 18.

In the form of reamer here illustrated the swinging cutters are shown asbeing made up of upper and lower heads 20 and 21 and roller cutters 22mounted on cutter pins 23 extending between the two heads. Thesecomposite cutters may be taken as typical of any other type of cuttermake-up. Each cutter, considered as a whole, is mounted on upper andlower vertical pivot pins 24 and 25 which pivot pins are mounted in thebody above and below the body recesses 26 into which the cutters swingwhen contracted.

The push rods 30 extend downwardly and outwardly from chamber 12,through openings 31, into the body recesses 26; and, at their lowerends, engage and bear upon the upper cutter heads 20. These push rodsare preferably provided with heads 32 at their inner ends, and the ball16 rests upon these heads. Springs 34 may be provided under wardswinging of pivots24 from the the push rod heads if desired for theurthen the cutters may be contracted either by pose of returning thepush rods and b 16 rotating the tool left-handedly or by pulling to theposition of Figure 1 without the inform that function.

With reference to Figures 1 and 3, showing the parts in contractedposition, .it will be seen that the upper heads ave recesses in whichthe lower outer ends of the push rods bear. These recesses are so shapedthat the ends of the push rods bear against the heads at points somewhatofi direct alinement with the centers of cutter pivots 24 so thatoutward longitudinal movement of the push rods will swing the cuttersaround their position shown in Figure 3 toward such a position as shownin igure 4.

In the normal position of the parts ball 16 closes or substantiallcloses passage 14 by seating or substantially seatin on seat 15.Hydraulic pressure ap lied to t e circulation passage 11a causes t eball to be forced downwardly and thereby forces the push rods down andout to such positions as shown in Figures 2 and 4. The openings 31through which the push rods pass are made somewhat tapering, or largeenough that the push rods may move lon 'tudinally outwardly, and theirouter enfs follow the cutter heads, without any of the parts binding.

When theputters have been swung outwardly somewhat towards such aposition as shown in Fig. 4, then the roller cutters 22 engage the sideof the hole. Upon rotation of the-reamer body in the direction indicatedbit; the arrow in Fig. 4, this wall contact of t e cutters drags thecutters further around in the expanding direction indicated by the darrows, swinging about their swinging pivots 24. The cutters thus willbe swung further around to such a position as shown in Fig. 4, whereinthe points of contact with the wall are well outside the swingingcenters 24; and in that position the cutters will be held expandedwithout any further pushing action from hydraulic actuation. It is not'neces sary that the cutters swing outwardly and around far enough thatthe roller centers are exactly radially out from swinging centers 24, inorder to accomplish the action last explained; the position of therollers substantially outward from swinging centers 24, or somewherenear the position radially outward from those swinging cutters willsuflice. Thus, the cutters may swing outwardly to expanded positions,near, or to, or beyond the radial position, as is desired.

The cutters will remain in their expanded positions until desired to becontracted,'regardless of whether the hydraulic pressure continues. Whenit is desired. to contract the cutters; hydraulic pressure isdiscontinned, allowing the ball and push rods to move back to theirpositions of Figure 1, and

the cutters having to perit up into the casing. It .is preferable tocontract by casing contact; and for this purpose upper heads 20 areprovided with diagonal outer surfaces 50 (see Figures 1, 2, 3 and 4which surfaces engage w1th the lower end 0 the casing or casing shoeand, by their diagonal reaction, push the cutters inward- .ly as theyare drawn upwardly against the casing.

' I claim:

1. In an expansive reamer, a body havin a fluid circulation passage,cutters mounte on the body on vertical swinging axes and adaptedto'swing from an inner contracted position outwardly andcircumferentially about the body to outer expanded positions wherein theoutermost cutting element of each cutter is outside the swinging axis,so that engagement of the cutters with the wall of the hole keeps andholds the cutters in expanded position; and hydraulically actuated meansto move the cutters from their contracted positions toward theirexpanded positions, said last mentioned means embodying cutter movingmembers impelled by fluid pressure in the fluid circulation passage ofthe body.

2. In an expansive reamer, a body having a fluid circulation passagetherein, cutters mounted in the exterior parts of the bod andconstrained to lateral movement wit reference thereto, push rodsengaging the cutters and extending diagonally upwardly and inwardly intothe movable member in the y, and a vertically boddy, upper inner ends ofthe re s,

engaging the and movable ownwardly under action of fluid pressure in thefluid passage In witness that I claim the foregoing I have hereuntosubscribed my name this 9thday of Dec, 1930.

MlLLIO FRANK ALOI.

